irqdomain/debugfs: Provide domain specific debug callback

Some interrupt domains like the X86 vector domain has special requirements
for debugging, like showing the vector usage on the CPUs.

Add a callback to the irqdomain ops which can be filled in by domains which
require it and add conditional invocations to the irqdomain and the per irq
debug files.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Juergen Gross <jgross@suse.com>
Tested-by: Yu Chen <yu.c.chen@intel.com>
Acked-by: Juergen Gross <jgross@suse.com>
Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Marc Zyngier <marc.zyngier@arm.com>
Cc: Alok Kataria <akataria@vmware.com>
Cc: Joerg Roedel <joro@8bytes.org>
Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Rui Zhang <rui.zhang@intel.com>
Cc: "K. Y. Srinivasan" <kys@microsoft.com>
Cc: Arjan van de Ven <arjan@linux.intel.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Len Brown <lenb@kernel.org>
Link: https://lkml.kernel.org/r/20170913213152.512937505@linutronix.de

include/linux/irqdomain.h

@@ -40,6 +40,7 @@ struct of_device_id;
 struct irq_chip;
 struct irq_data;
 struct cpumask;
+struct seq_file;
 
 /* Number of irqs reserved for a legacy isa controller */
 #define NUM_ISA_INTERRUPTS	16
@@ -104,7 +105,6 @@ struct irq_domain_ops {
 	int (*xlate)(struct irq_domain *d, struct device_node *node,
 		     const u32 *intspec, unsigned int intsize,
 		     unsigned long *out_hwirq, unsigned int *out_type);
-
 #ifdef	CONFIG_IRQ_DOMAIN_HIERARCHY
 	/* extended V2 interfaces to support hierarchy irq_domains */
 	int (*alloc)(struct irq_domain *d, unsigned int virq,
@@ -116,6 +116,10 @@ struct irq_domain_ops {
 	int (*translate)(struct irq_domain *d, struct irq_fwspec *fwspec,
 			 unsigned long *out_hwirq, unsigned int *out_type);
 #endif
+#ifdef CONFIG_GENERIC_IRQ_DEBUGFS
+	void (*debug_show)(struct seq_file *m, struct irq_domain *d,
+			   struct irq_data *irqd, int ind);
+#endif
 };
 
 extern struct irq_domain_ops irq_generic_chip_ops;

kernel/irq/debugfs.c

@@ -81,6 +81,8 @@ irq_debug_show_data(struct seq_file *m, struct irq_data *data, int ind)
 		   data->domain ? data->domain->name : "");
 	seq_printf(m, "%*shwirq:   0x%lx\n", ind + 1, "", data->hwirq);
 	irq_debug_show_chip(m, data, ind + 1);
+	if (data->domain && data->domain->ops && data->domain->ops->debug_show)
+		data->domain->ops->debug_show(m, NULL, data, ind + 1);
 #ifdef	CONFIG_IRQ_DOMAIN_HIERARCHY
 	if (!data->parent_data)
 		return;

kernel/irq/irqdomain.c

@@ -1810,6 +1810,8 @@ irq_domain_debug_show_one(struct seq_file *m, struct irq_domain *d, int ind)
 		   d->revmap_size + d->revmap_direct_max_irq);
 	seq_printf(m, "%*smapped: %u\n", ind + 1, "", d->mapcount);
 	seq_printf(m, "%*sflags:  0x%08x\n", ind +1 , "", d->flags);
+	if (d->ops && d->ops->debug_show)
+		d->ops->debug_show(m, d, NULL, ind + 1);
 #ifdef	CONFIG_IRQ_DOMAIN_HIERARCHY
 	if (!d->parent)
 		return;